PM coy on Dutton's gay marriage solution

If the federal government is working on an alternative path to legalise same-sex marriage, the prime minister isn't saying.

Immigration Minister Peter Dutton, one of the government's leading conservatives and an opponent of gay marriage, is said to be working behind the scenes on a process over which the coalition maintains control.

Together with Mathias Cormann, another cabinet minister opposed to same-sex marriage, Mr Dutton is pushing for a postal vote plebiscite to be held before a parliamentary vote on the issue, Fairfax Media said.

Unlike a regular poll, a postal vote would not require legislation, voting would be voluntary and would be far cheaper to administer.

Malcolm Turnbull is understood to be wary of the idea.

But the prime minister wasn't giving any clue when quizzed by reporters in Canberra on Wednesday.

"We went to the election with a policy for a plebiscite which would give every Australian a say," he said.